This invention relates to a cooling device for an engine and more particularly to an improved, simplified and compact expansion chamber arrangement for the liquid coolant of a liquid cooled internal combustion engine.
Many forms of internal combustion engines are cooled by liquid cooling systems that include a cooling jacket for the engine, a heat exchanger for exchanging heat from the liquid coolant of the engine to the surrounding atmosphere and conduits and a circulating arrangement for circulating the coolant between the heat exchanger and the engine cooling jacket. As is well known, the coolant temperature can vary quite widely during operation and when the engine is not being run. Ambient temperatures can reach quite low temperatures and the normal operating temperature of the engine is substantially above ambient and may be near or even above the boiling point of water. That is, it is the frequent practice to use a coolant that is other than pure water and to pressurize the cooling system so that the boiling point will be raised even further. The efficiency of the engine and its cooling system can be increased if the operating temperature of the cooling system is above the boiling point of water. Of course, these extreme variations in coolant temperature can give rise to substantial volume changes in the coolant. It has, therefore, been the practice to provide an expansion chamber which communicates with the main cooling system and into which excess fluid can be displaced as the fluid is heated. When the system cools back down, the coolant will flow from the expansion chamber back into the main cooling system. Although such devices are obviously advantageous, the volume of the expansion chamber must be adequate to assure that it can contain the total and maximum anticipated excess volume. As a result, the size of the expansion chamber may in many instances be larger than actually required due to the fact that the ambient temperature may not be as low as the maximum design low temperature. Although with such engine applications as in powering motor vehicles this is satisfactory, in many other applications the use of such large expansion chambers can be disadvantageous. Also the use of fixed volume expansion chambers means that air must be present in contact with the coolant which is not always desirable.
It is, therefore, a principle object of this invention to provide an improved cooling system for internal combustion engines.
It is a further object of this invention to provide a variable volume expansion chamber for a liquid cooled internal combustion engine.